1. Field of the Invention
The present invention relates to spacecraft. In particular, the present invention relates to a hinge mechanism for deploying components of a spacecraft.
2. Description of the Related Art
Satellites are generally designed for two different environments.. The first is the environment to which the satellite will be subjected during launch. At launch, a satellite must be packed into a launch vehicle, generally requiring that the satellite fit within some specific confined space. During launch, a satellite is often subjected to high physical stresses such as g-loading and vibration.
The second environment is the orbital environment. Unlike the launch environment, once in orbit the satellite is generally subjected to very light force loading and vibration, if it is subject to any at all. Furthermore, the structure may generally be large or unwieldy in this environment without any adverse effect, since there are generally no size constraints or physical loads imposed by gravity or air resistance upon the satellite once deployed.
Because of the difference between these two environments, it is common to design satellites and other components of spacecraft such that they have two different configurations: one used for launch and one used while in orbit. This allows the designer of the satellite or spacecraft to take advantage of the greater design flexibility available in the orbital environment, while still providing a robust design that fits within the necessary physical limits required for the launching process.
In order to adjust the satellite from one configuration to the other, it is common to use collapsible members, hinges, and other moving parts. There is therefore a need for continued development of improved devices such as hinges to facilitate the transformations of satellites from their launch to their orbital configurations.
In one preferred embodiment of the present invention, a hinge mechanism is constructed which allows a base panel and a folding panel to be deployed from a stowed configuration into a deployed configuration. In the stowed configuration, the panels face each other and are connected by the hinge mechanism which attaches to a lateral edge of each panel. Other panels may be disposed in-between the two panels. The hinge is connected to the folding panel by a first arm and to the base panel by a second arm which is connected to a telescope fitting which slides within a telescope housing mounted within the base panel. A cable is threaded from the folding panel through the hinge mechanism and over a number of pulleys which are disposed upon the arms of the hinge mechanism. The cable is then threaded along the telescope housing and onto a cable spool. The spool is driven by an actuator in order to control the tension in the cable.
When the actuator is used to increase the tension in the cable, the hinge mechanism unfolds, rotating the folding panel with respect to the base panel. When the rotation is complete, the hinge mechanism is drawn into the telescope housing by the tension of the cable, pulling the folding panel snugly against the base panel such that their connected lateral edges now press against one another. In this deployed configuration, the panels are disposed so that no gap is left between the sides of the panels.